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|Title:||Hydrophobic flocculation characteristics of calcite and effects of some inorganic dispersants|
|Keywords:||Calcite;Hydrophobic flocculation;Sodium dodecyl sulphate;Aero 845;Dispersant|
|Abstract:||Hydrophobic flocculation characteristics of calcite mineral were investigated using sodium dodecyl sulphate (SDS) and Aero 845. Calcite suspensions could be flocculated by these anionic surfactants in the pH range of 9.3-11.5. Especially SDS was more effective on the calcite suspensions at pH values lower than 10.5. The flocculation of calcite with SDS and Aero 845 increased rapidly with increasing surfactant concentration. However, it started to decrease at concentrations higher than 30 mg/L for Aero 845 and 50 mg/L for SDS. It was found that the maximum aggregation degree of calcite particles could be achieved with a stirring speed of 500 rpm and a flocculation time of 3 min. The effects of sodium silicate, sodium polyphosphate and sodium phosphate, used as inorganic dispersants, on the flocculation of calcite were also studied. In the presence of sodium silicate and sodium polyphosphate, the flocculation power values obtained with both surfactants decreased with increasing dispersant concentration till approximately 0.5 and 1 g/L concentrations, respectively. Also, the flocculation of calcite with Aero 845 and SDS decreased towards 0.5 and 1 g/L concentrations of sodium phosphate, respectively. At higher dispersant concentrations, these power values remained relatively constant for sodium silicate, and different effects were also observed for other dispersants depending on surfactant type used in the experiments. In addition, it was found that sodium silicate was more effective to disperse the calcite suspensions with SDS and Aero 845.|
|ISSN:||0975-0991 (Online); 0971-457X (Print)|
|Appears in Collections:||IJCT Vol.13(5) [September 2006]|
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